Decades-long loyalties are being tested in a divided Republican establishment

The agony is palpable. It comes through in conversations, in awkward moments of silence, in audible sighs.

Ordinarily politics is full of the crassest instincts, the basest motives, the meanest impulses. But this is different. This is a matter of loyalty, friendship, battles fought, values shared — and of two special fathers, each with a political legacy of his own.

This may be the toughest decision of the age for the Republican establishment. The looming choice between two former governors, Mitt Romney of Massachusetts and Jeb Bush of Florida, has induced an unease without precedent in modern American politics.

Few Democrats stewed over the choice between John F. Kennedy and Hubert H. Humphrey in 1960. The two were from different regions, possessed different outlooks, had different styles, moved in different circles.

No Republicans wrestled with the choice of Gerald R. Ford or Ronald W. Reagan in 1976. The two had almost nothing in common.

Even the two reform-minded Ivy Leaguers — one Harvard, the other Princeton — who fought for the 2000 Democratic nomination produced little agita. Vice President Albert Gore Jr. and former Sen. Bill Bradley drew from different strains in the Democratic Party.

This early 2016 campaign anxiety began the other day when Mr. Romney, who already has run for president twice, indicated he is contemplating a third campaign even as Mr. Bush, son and brother of a president, was assembling the rudimentary elements of a presidential campaign of his own.

“This is very hard for someone like me,” says former Gov. John H. Sununu of New Hampshire. Mr. Sununu was an indispensable element in the presidential campaigns of both George H.W. Bush and George W. Bush and served as chief of staff in the elder Mr. Bush’s White House. But he played a leadership role in the two Romney presidential campaigns, too.

“I have too many friends running in this election,” he says.

Mr. Sununu is not alone. Says a leading business executive who raised money for both Mitt Romney and Jeb Bush’s presidential brother: “I’m going to try to stay away from the telephone.”

So, presumably, will Gov. Nikki R. Haley of South Carolina. Mr. Romney campaigned for her. She’s very close to Mr. Bush. The same goes for former Sen. Judd Gregg of New Hampshire, whose family has lived in New Hampshire since 1718 and has been a presidential power broker in the state since his father, Hugh Gregg, became governor in 1953.

The senior Mr. Romney asked the senior Mr. Gregg to run his 1968 presidential campaign in New Hampshire, and the younger Mr. Gregg was an ardent backer of the younger Mr. Romney.

That counts for a lot. But will this count for more?: The senior Mr. Gregg ran the senior Mr. Bush’s New Hampshire presidential campaign in 1980, and the junior Mr. Gregg ran the junior Mr. Bush’s campaign in the state in 2000.

Mr. Romney and Mr. Bush are not sunshine and snowstorm versions of the same political profile. But they draw from the same fundraiser, organizer and activist pool. They’re scions of political giants, firmly in the establishment wing of the Republican Party, each with prep-school backgrounds and personas. They both have strong, imaginative records as governors — and cool temperaments. And they each claim a deep well of family and personal loyalty. Within the GOP establishment, loyalty is the virtue that is valued most — and is causing the most anxiety.

“A lot of phone calls are being made to the same people,” says a veteran New Hampshire political counselor, by anyone’s measure one of the most valued catches as candidates assemble their kitchen cabinets. “And none of us knows what we are going to do. It’s a nightmare to choose between a Romney and a Bush.”

Adds Mr. Sununu: “Everybody has the same problem. All of us are close to both families.”

That closeness is literal, especially in New Hampshire. Both men have roots in neighboring states, Mr. Romney in Massachusetts, where he built his business before becoming governor, and Mr. Bush in Maine, where his family has spent the summer for a century.

Mr. Romney finished second in Iowa in 2008 and 2012 (the latter by only 34 votes) and Mr. Bush’s father and brother won Iowa as challengers in 1980 and 2000 and as incumbents in 1992 and 2004. But the Hawkeye State is not particularly congenial territory for either in 2016, when a gaggle of religious, social and economic conservatives will be contenders.

That heightens the stakes for them in New Hampshire, the first primary state, likely to be held eight days after Iowa’s caucuses. And already political theories are flying like snowflakes in the White Mountains:

Will there be a generational divide, with younger establishment figures leaning toward Mr. Bush because he’s talking about modern topics like immigration and the Common Core? Will the establishment lean toward Mr. Romney because he’s more versed in foreign policy, having honed his diplomatic perspective in a presidential debate against Barack Obama and thus more adept in taking on former Secretary of State Hillary Rodham Clinton?

Will all this agony involving Mr. Bush and Mr. Romney draw the oxygen away from the nascent campaign of Gov. Chris Christie of New Jersey? Is the ultimate beneficiary of all this Sen. Rand Paul, who has a two-generation heritage of his own by virtue of his father, Rep. Ron Paul of Texas, who attracted 56,848 votes in the 2012 New Hampshire primary (nearly 23 percent)?

The closest comparison to the 2016 angst may be the struggle between Mr. Romney’s father, Gov. George Romney of Michigan, and former Vice President Richard M. Nixon in 1968. But the elder Mr. Romney withdrew a dozen days before the New Hampshire primary and his supporters were far more congenial to Gov. Nelson A. Rockefeller of New York than to Mr. Nixon.

It will not surprise you to learn that the elder Mr. Gregg then ran Mr. Rockefeller’s campaign in New Hampshire. The Bushes and the Romneys may be everywhere, but the Greggs — two of them have occupied the governor’s office in Concord — are everywhere, too. And every place in the Republican Party where there is a Bush, a Romney or a Gregg — and countless others — there is great unease today.

David Shribman, a Pulitzer Prize winner in journalism, is executive editor of the Pittsburgh Post-Gazette.

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